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SCREEN
stencil is a precision engineered
template for the image.
Once you are satisfied that stencil
production is under control and
capable of producing consistent
stencils, move on to machine set up,
Aim for zero defects and send the
skips packing
ink preparation and print production.
Drying and curing is a key aspect of
most forms of screen printing. It is also
an area where energy costs can get
out of hand if the dryers are inefficient
or incorrectly set. Cure levels
determine the effectiveness of inter-
coat adhesion particularly when using
UV curing and reactive curing systems.
Drying will affect registration and it is
important to recognise where miss-
registration is caused either during
stencil production, printing or drying.
Sometimes all areas will have an
effect to a greater or lesser extent.
The only way to manage these and
other issues out of the process is with
effective agreed standard operating
procedures, rigorously applied. Those
working to the SOPs must recognise
the effectiveness of such procedures.
In screen printing it is easy to
compromise the effectiveness of an
SOP with a small deviation from
procedures that throws the process out
of tolerance.
Standard operating procedures will
enable you to continuously improve
the process from a firm foundation of
best practice.
quotation and works order generation. Production planning and machine loading
have a significant effect on efficiency. Assess what degree of historical Time to get lean
information is used in the creation of costing and determine the accuracy of the For those who really want to shine, it's time to address lean manufacturing. This
quote verses actual production cost equation. In time this will demonstrate what is the principle of getting the right things, to the right place, at the right time, in
type of work is most profitable and you can determine your willingness to take the right quantity to achieve perfect work flow while minimising waste and
on less or non-profitable work. being flexible and able to change.
The best change scenario is to improve the process to bring all jobs into an To achieve this, it is essential to reduce variables in the process. It may be that
acceptable level of profitability. This is even more important because the market equipment is unsuitable due to maintenance deficiencies. A screen printing
is in recession. Getting additional volume is difficult, but getting more from less machine that is out of alignment is a reject production machine. You may have
is a challenging yet attainable outcome. equipment that is unable to maintain a consistent result, necessitating capital
investment. Making this kind of judgement is only possible when the potential
Aim for continuous improvement variables are understood, as well as how to rectify them.
Standard operating procedures (SOP) are a vital part of improvement. They need The way forward relies on benchmarking production performance, adjusting
to provide a clear description of how each process is carried out, ensuring SOPs to suit, then embedding the improved practices in production and providing
consistency throughout the workforce. There should be sufficient information in a platform and milestones for continuous process improvement.
the SOP that the operative could follow the instruction and complete the job Don’t expect this to be an overnight exercise. It is vital to explain to the
without having to ask additional questions. The aim is to continuously improve workforce what you are trying to achieve. Removing cost does not mean
each process, updating the document as methods evolve and develop. redundancy, it means higher profits and having a fit company ready for
A key factor in achieving consistent results is the production of the stencil. This opportunities as the arise. Some of the best ideas for process improvement come
is an aspect of screen printing where some industrial screen printers have a great from the people who are carrying out the tasks. Sometimes a temporary worker
deal of experience, particularly in the development and operation of stencil who has no experience will say “Why do you do that?” The answer is often
production units for biomedical sensors. The dimensional tolerance of stencil because that is the way it has always been.
thickness and image size are very tight and the techniques applied in this Times have changed and if you don’t adapt and improve, you may not
application are relevant to all other high quality screen printing applications. The be here to reap the rewards of the upturn.
| 10 | Screen Process & Digital Imaging | May 09 Visit us online at www.spdi-online.com
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